Rethinking the Underwear Bomb's Impact

(Discover)  By Andrew Moseman
Reprinted with permission from Discover

We gave the BBC a hard time for going a little overboard in declaring the Large Hadron Collider a broken-down mess. But here's something cool: In a new documentary, a team simulated the blast that "Underwear Bomber" Umar Farouk Abdulmutallab tried to create on Christmas Day last year. Their finding: Even if he had blown up the bomb successfully, it wouldn't have been enough to take down flight 253 from Amsterdam to Detroit.

Dr John Wyatt, an international terrorism and explosives adviser to the UN, replicated the conditions on board the Detroit flight on a decommissioned Boeing 747 at an aircraft graveyard in Gloucestershire, England .

Wyatt used the same amount of the explosive pentaerythritol that the bomber carried, about 80 grams, which packs about the punch of a hand grenade. They put it on the same seat and lit off a controlled explosion, which sent a shock wave through the aluminum exterior.

The metal was permanently bowed out, and a handful of rivets were punched out, but no gaping holes appeared. The pressurized air inside the cabin would have slowly leaked out .

Wyatt and his cohorts say that wouldn't have been life-threatening, and it wouldn't have brought down the plane. However, the blast would probably have killed the bomber and the person next to him. And things wouldn't have been all sunshine and roses for the survivors, either. Team member Captain J. Joseph said the noise and the smoke would have been awful, "not to mention the parts of the bodies that were disintegrated as part of [the explosion." Their eardrums could have ruptured, too.

This wasn't a perfect simulation: Wyatt tested a 747, while the actual bomber flew aboard an Airbus 330. And the conditions inside were normal atmospheric pressure, not the pressurized state of a plane in flight. But Wyatt argues that the Airbus' stronger composite materials mean it would have fared even better than his test aircraft. As for the pressure? It's over so quickly that the difference in pressure wouldn't make a difference," said Wyatt. "By the time the shock wave got to the door the pressure would have normalized."

In Britain, the documentary (called "How Safe Are Our Skies?") aired on BBC Two. You can still see it on their iPlayer. For those of us here in the United States, the Discovery Channel broadcasts it tonight (Thursday) at 10 PM EST.

This article was written by Discover'sAndrew Moseman.

[KeithDrippingSprings]

First, the bomber was a chemical engineer, lesson - don't go to that college.

Second, a mechanical or aeronautical engineer conducted the test so things like altitude and pressures would have been some of the many variables they used to evaluate the data. Lesson - ludvig, where did you go to college?

Third, the terrorist aren't the sharpest rocks on the pile anyway but I would suppose that when the bomb didn't work they knew something was wrong. And the way things turned out they won anyway. Without any damage to the plane or any loss of life the terrorist made the most powerful nation in the world conduct their business in fear. That is a terrorist job. Lesson - scottyusa, classified information makes us less safe not more.

[ddog88]

The test clearly does not take into account "sky gas". Two cans of beans, an M-80, and some exploding underoo's and the USA is set for 8 more years of war against goat farmers on the other side of the planet.

[ludvig1-2009]

I would find the test method used to be dubious. On our planet earth at ground level the outside air pressure on the plane would be 14.7 pounds on each square inch pushing inward on the plane. At 30,000 feet, I don't know what it would be, but it would be considerably less, so there would be less outside pressure pushing in on the plane and a greater differential pressure pushing outward from inside the plane than what the tester's used unless they had a vacuum seal of some type over the tested area.

[sfe2010]

I see..
you think you know more than the experts. I bet you believed Iraq possessed WMD though, didn't you....

[scottyusa]

To be sure, this should be classified information!

[scottyusa]

It doesn't matter you idiots. Nothing like telling the terrorists to use more next time.

[start99]

So...tell me...why did they need to test it. The guy is guilty for an attempt. Window seals and rivets damaged.Doesnt prove a thing..the test wasnt flying. Dips

[bcpats]

So with this finding that the underwear bomber was really not a threat after all - - - maybe his sympathisers will rally 'round and get a lenient trial so he go off, improve the technique and try all over again - - with more impact and deadly results.